U.S. Army Coffee cup
This is recommended equipment for all NATO participants.
A coffee (or tea) cup can be a nice addition when in camp. They tend to keep hot drinks hotter longer than a canteen cup and are a little easier to drink out of as well.
There are any number of options for coffee cups from original issue cups such as the above pictured USGI Bakelite cup, unit specific cups, commemorative cups, kitschy 1980s cups, to just plain old coffee cups. Bring one along, you'll be glad that you did.